feat: implement 60-second analysis cache TTL for high-frequency airport cities

tests/test_analysis_ttl.py

@@ -0,0 +1,12 @@
+from web.analysis_service import _analysis_ttl_for_city
+from web.core import CACHE_TTL
+
+
+def test_high_frequency_airport_cities_use_one_minute_analysis_cache():
+    assert _analysis_ttl_for_city("chongqing") == 60
+    assert _analysis_ttl_for_city("shanghai") == 60
+    assert _analysis_ttl_for_city("singapore") == 60
+
+
+def test_non_high_frequency_city_keeps_default_analysis_cache_ttl():
+    assert _analysis_ttl_for_city("new york") == CACHE_TTL